Interesting setup you have there there Rocco and a good signal in the recording. I need to do some more checks on my 1.5m dish because the received signal really isn't as good as it should be but it should certainly be good enough to decode QRA64 or Q65.
Nice to see your words about Dom I8CVS on your website. Looking back through my log book he was my third contact on AO40 nearly 20 years ago. The antenna I was using then was the same one I'm using for 10GHz EME now!
73 Chris G4SDG
Hello Rocco,
Thanks for the report. I was assuming that it was operator error at my end but perhaps not if you're having no success either. I'm using WSJT-X v 2.4.0.rc4 and SDRConsole 3.26 with Doppler tracking enabled. The FunCube dongle isn't GPS locked but it received the QRA64 alright last year.
What size antenna are you using?
73 Chris G4SDG
A bit off topic but can anyone confirm which modulation scheme DL0SHF is currently using? I thought it had changed from QRA64 to Q65-60D but I can't decode either with WSJT-X despite having decent signal levels. I was decoding the QRA64 fine when I tried last year.
73 Chris G4SDG
Hello Chris,
Over in the SDR-Console forum where I subsequently posted my observation Simon said he was aware that the transmit issue was still present in v25 so it’s interesting that you don’t experience it.
I find that the receive central spur suppression is poor with the Lime compared to my Funcube dongle despite having adjusted the levels as recommended. I’ve not tried my Pluto on SDR-Console as it’s built into a Langstone along with a Pi but on the next rainy day I might see what it’s like. I’ll look into the Lime transmit a bit more closely than I’ve done previously.
73 Chris G4SDG
Thanks Andreas and Keith. As there was no warning on the download page about lack of Lime transmit support as there had been with 3.0.24 I assumed(!) it was resolved but apparently not. A sign of things to come I guess as a quite complicated program copes with more hardware and ever greater functionality. Gone are the days of having the same main station rig for twenty years!
73 Chris G4SDG
Hi all,
Is anyone else experiencing problems with the Lime-Mini transmit and SDR-Console v3.0.25 64bit? Mine will transmit once but then when I hit the "Transmit" button again nothing happens. The receive carries on functioning. I have to stop and restart the Lime on SDR-Console but then it again only transmits once. "Tone", "Tune" and SSB act in the same manner. I've rolled back to 3.0.19 (unfortunately the last download version I have on file - when will I learn!) and that works OK. I had previously been running 3.0.23 as 3.0.24 apparently already had a known Lime transmit problem. I've checked the Lime's firmware and according to LimeSuite it's up to date and showing FW:6 HW:2 Protocol:1 GW:1.28. PC is an Intel 8th Gen NUC i7-8559U 2.7GHz with 32Gb.
Chris G4SDG
Display MoreHi,
I apologize for the late response - the question has already been answered by others.
I experienced a computer crash last week, now I'm recovering.
If you have any questions, I'm available.
Regards,
Marian
It's a good modification Marian and I'm now also using a similarly modified LNB on my 10GHz terrestrial antenna. The serial numbers of my two were a hundred or so different from yours. A friend of mine purchased a couple of Opticum LTP-04h LNBs a few days ago and discovered that internally they are yet another different board but with a Rafael Micro RT320M chip.
73 Chris G4SDG
I've done the modification and it's working well so thanks for the information Marian. I seem to have gained a couple of dB S/N compared to my old modified GL-202 LNB too.
73 Chris
Thanks Peter. It’s probably my eyesight but it wasn’t clear to me in Marian’s image whether it was that track that was cut and the point of the red arrow wasn’t actually on it - seemed a bit to the right. “Measure twice - cut once” is the saying but in this case “ask twice” 😀
73 Chris
Hello Marian,
I just wanted to double check the cut to the RDA3567. Is it at the red line shown in my photo below?
Regards Chris G4SDG
Although the Limi Mini has a connector for external reference I believe that it is necessary to move (with a soldering iron) a zero ohm surface mount resistor in order to be able to use it. I don’t feel confident doing this so use mine with the internal reference and it drifts a small but annoying amount during each over as the Lime warms up.
73 Chris
Hello David,
The filtered amp with good gain is a much needed item. I've dabbled with a few uplink options for QO-100 from on Day #1 an SG-Labs U/C, Spectrian amp and a 25 turn helix to the current set-up of a Lime-Mini, MHL21336 and "8W" Wifi amp to a 90cm off-set, and along the route I tried the "Easy-100" modular system with ADL5350 mixer and a handful of low power modules and WiFi amp. The MHL21336 works well but does get warm (OK - hot) and my version of the 5W DJ0ABR amplifier was a few dB short on expected gain. I have three "8W" WiFi amplifiers and none of them get produce more that 4 watts saturated and one of them was 4dB less gain than the other two. Overall, gain in the middle section has generally been a problem.
Ole OZ2OE - I checked my Lime Mini and saw similar jumps in the output settings especially in the 80-90% area. Quite apart from this hardware problem I think that SDR Console would be easier to use if it had Up/Down buttons rather than a slider. Perhaps my old fingers are having trouble using the mouse with enough sensitivity!
I've got a problem with my analyser so I haven't been able to check the output spectrum.
73 Chris
Hello Nicolas,
How long is the cable between the LNB and what type of cable is it? Is there anything else in that path - a DC power inserter? Or are you peaking the antenna by looking at the NB beacon using a laptop very close to the antenna?
73 Chris G4SDG
Hello Nicholas,
I believe that with a correctly pointed 80cm antenna and reasonable receive system you should be able to see the transponder noise floor and once you see that then the uplink S/N as "seen" by the transponder is largely the limiting factor. There is a thread here QSB on the beacon signal? where the measurement of the beacon S/N using SDR Console is discussed. Bandwidth settings have an impact on the figure but for his settings Peter DB2OS said 38dB S/N was usual for the lower beacon once you see the transponder noise floor. That's what I see with my 60cm with an unmodified Goobay GL202 LNB.
73 Chris G4SDG
Hello Ole OZ2OE,
I will try out your tests on my Lime-Mini to see if my results are similar. How have you got the two tones set?
When you mention 90% drive, is that with your SDR Console "Drive" configuration for the Lime set to the default spread. With mine like that the 90% equates to just over 6dB backed off from maximum.
73 Chris
Regarding SDR Console and the LimeSDR-Mini, I don't understand why changing the TX Antenna actually changes the output level when there's only one transmit port but it does. I'm using the latest Console software version. I checked my setup with a power meter yesterday and Band 2 is 11.5dB lower than Band 1. Selecting Auto did give the correct output.
73 Chris G4SDG
I'm using a LimeMini with SDR Console and when I recently updated the software my output power dropped right off by 10 or more dB. As I'm not transmitting that often I didn't immediately connect the two things and spent a while looking for hardware problems. Eventually it turned out that the wrong transmit output was selected in SDR Console and going back to TxAnt: Band1 restored my power level.
73 Chris G4SDG
Hello Peter,
I was running a much older version of SDR Console (3.0.9) and just comparing the power in the beacon and with the same bandwidth of noise floor next to it for a rough ratio. I've updated to 3.0.18 and using the SNR function get the same 38dB as you.
73s Chris
Thanks Peter,
I thought I was but perhaps not in that case. I will do some investigating tomorrow if the weather is reasonable.
73s Chris
That's quite weak, even for a 60cm dish.. perhaps you are on a side-lobe or the window is metalized and has attenuation. Make sure you have AZ/EL optimized in several iterations, also don't forget the tilt/skew of the LNB.
6dB variation seems a lot.. Unless there is heavy rain or big clouds, I see almost have no variation.. the CW beacon is 38dB over the noise (in SDR console) here on a 80cm dish..
How are you measuring that 38dB Peter? I don't see that on my 90cm but I do see the transponder noise floor so I must be doing something wrong with SDR Console.
73 Chris
